The present invention relates to wave guide engineering practiced for the purpose of transmitting electromagnetic energy from a transmitter to a receiving apparatus; and more particularly the invention relates to the transition from a wave guide to a rectangular input of the apparatus which is to receive the electro-magnetic energy.
Wave guides are used, for example, for connecting high frequency transmitters to equipment that needs such energy, for example, appropriate heaters. In many such instances only relatively short path lengths have to be bridged so that the lengths of the wave guides are, for example, from two to five meters. If the equipment so supplied with HF energy is a high frequency heater, the wave lengths are in the Gigahertz range. It is common practice to provide the equipment receiving such energy with an input for connection to a wave guide and having a rectangular cross sectional contour. This being almost a standard kind of equipment designed, it is also common practice to use a more or less rigid, rectangular wave guide for connecting the transmitter to the equipment. It was found, however, that such a rectangular wave guide has a significant disadvantage in that it can be used in a simple fashion only in those rare instances where the path to be traversed is on a straight line. Much more common, however, is a situation in which the transmitter output and the equipment input are not on a straight line of sight so that level differences or lateral displacements have to be bridged through appropriately bent portions. The use of rigid wave guides has also the disadvantage that once a connection is made, position changes of the interconnected equipment are no longer possible.